/*********************************************************************
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 *
 * Author: Steve Macenski (steven.macenski@simberobotics.com)
 * Purpose: Structure for handling camera FOVs to construct frustums
 *          and associated methods
 *********************************************************************/

#ifndef FRUSTUM_H_
#define FRUSTUM_H_

// Eigen
#include <Eigen/Geometry>
// STL
#include <vector>
#include <cassert>
// OpenVDB
#include <openvdb/openvdb.h>
// msgs
#include <geometry_msgs/Point.h>
#include <visualization_msgs/Marker.h>
#include <visualization_msgs/MarkerArray.h>
#include <geometry_msgs/Quaternion.h>
#include <geometry_msgs/PointStamped.h>
#include <geometry_msgs/Pose.h>
// ROS
#include <ros/ros.h>

namespace geometry
{

// visualize the frustum should someone other than me care
#define VISUALIZE_FRUSTUM 0

// A structure for maintaining vectors and points in world spaces
struct VectorWithPt3D
{
  VectorWithPt3D(const double& x_, const double& y_, \
                 const double& z_, const Eigen::Vector3d& p0) : \
                 x(x_), y(y_), z(z_), initial_point(p0)
  {
  }
  
  VectorWithPt3D(void) : x(0.), y(0.), z(0.)
  {
  }

  inline VectorWithPt3D operator*(double a)
  {
    return VectorWithPt3D(a*x, a*y, a*z, initial_point);
  }

  // given a transform, transform its information
  void TransformFrames(const Eigen::Affine3d& homogeneous_transform)
  {
    Eigen::Vector3d vec_t = homogeneous_transform.rotation() * Eigen::Vector3d(x,y,z);
    vec_t.normalize();
    x = vec_t[0]; y = vec_t[1]; z = vec_t[2];
    initial_point = homogeneous_transform * initial_point;
    return;
  }

  double x, y, z;
  Eigen::Vector3d initial_point;
};

// A class to model a depth sensor frustum in world space
class Frustum
{
public:
  Frustum(const double& vFOV, const double& hFOV,
          const double& min_dist, const double& max_dist);
  ~Frustum(void);

  // transform plane normals by depth camera pose
  void TransformPlaneNormals(void);

  // determine if a point is inside of the transformed frustum
  bool IsInside(const openvdb::Vec3d& pt);

  // set pose of depth camera in global space
  void SetPosition(const geometry_msgs::Point& origin);
  void SetOrientation(const geometry_msgs::Quaternion& quat);

private:
  // utils to find useful frustum metadata
  void ComputePlaneNormals(void);
  double Dot(const VectorWithPt3D&, const openvdb::Vec3d&) const;
  double Dot(const VectorWithPt3D&, const Eigen::Vector3d&) const;

  double _vFOV, _hFOV, _min_d, _max_d;
  std::vector<VectorWithPt3D> _plane_normals;
  Eigen::Vector3d _position;
  Eigen::Quaterniond _orientation;
  bool _valid_frustum;

  #if VISUALIZE_FRUSTUM
    std::vector<Eigen::Vector3d> _frustum_pts;
    ros::Publisher _frustumPub;
  #endif
};

} // end namespace

#endif
